glGetMinmax
GLGETMINMAX(3G) GLGETMINMAX(3G)
NAME
glGetMinmax - get minimum and maximum pixel values
C SPECIFICATION
void glGetMinmax( GLenum target,
GLboolean reset,
GLenum format,
GLenum types,
GLvoid *values )
PARAMETERS
target Must be GL_MINMAX.
reset If GL_TRUE, all entries in the minmax table that are actually
returned are reset to their initial values. (Other entries
are unaltered.) If GL_FALSE, the minmax table is unaltered.
format The of the data to be returned in values. Must be one of
GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_BGR, GL_RGBA,
GL_BGRA, GL_LUMINANCE, or GL_LUMINANCE_ALPHA.
types The type of the data to be returned in values. Symbolic con-
stants GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP,
GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT,
GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV,
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, and GL_UNSIGNED_INT_2_10_10_10_REV
are accepted.
values A pointer to storage for the returned values.
DESCRIPTION
glGetMinmax returns the accumulated minimum and maximum pixel values
(computed on a per-component basis) in a one-dimensional image of
width 2. The first set of return values are the minima, and the sec-
ond set of return values are the maxima. The of the return values is
determined by format, and their type is determined by types.
No pixel transfer operations are performed on the return values, but
pixel storage modes that are applicable to 1-dimensional images are
performed. Color components that are requested in the specified for-
mat, but that are not included in the internal of the minmax table,
are returned as zero. The assignment of internal color components to
the components requested by format are as follows:
-----------------------------------------
Internal Component Resulting Component
-----------------------------------------
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red
-----------------------------------------
If reset is GL_TRUE, the minmax table entries corresponding to the
return values are reset to their initial values. Minimum and maximum
values that are not returned are not modified, even if reset is
GL_TRUE.
NOTES
glGetMinmax is present only if GL_ARB_imaging is returned when
glGetString is called with an argument of GL_EXTENSIONS.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_MINMAX.
GL_INVALID_ENUM is generated if format is not one of the allowable
values.
GL_INVALID_ENUM is generated if types is not one of the allowable val-
ues.
GL_INVALID_OPERATION is generated if glGetMinmax is executed between
the execution of glBegin and the corresponding execution of glEnd.
GL_INVALID_OPERATION is generated if types is one of
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and format is
not GL_RGB.
GL_INVALID_OPERATION is generated if types is one of
GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
GL_UNSIGNED_INT_10_10_10_2, or GL_UNSIGNED_INT_2_10_10_10_REV and for-
mat is neither GL_RGBA nor GL_BGRA.
SEE ALSO
glMinmax(3G), glResetMinmax(3G), glGetMinmaxParameter(3G)
GLGETMINMAX(3G)
